I love it because in a great way is a good parallel to Zoro (contrary to what ALOT of people here don't get). Zoro is the 1 person who believes in Luffy more than anyone. He's also the first person willing to trash on his own dream to:
- Die for Luffy (i.e. Thriller Bark)
- Beg Mihawk to train him
That resolve is 100% a first mate's job (who I consider Zoro to be regardless of what labels are thrown vs what arent), and i definitely think it's what Oda is conveying here.
Because of this, Killer has been massively elevated in my book and now im really excited to see what Kid brings to the table here. Oda definitely is setting something up.